Properties of novel lithium insertion borocarbides

采用第一性原理计算表征了碳硼化镁锂（Li，Mg）BC的Zintle相，并将其作为锂离子电池负极活性材料。系统的第一性原理计算结合团簇展开技术和Monte Carlo统计热力学模拟预测了MgB_2C_2和LiMgB_3C_3之间的嵌锂氧化还原电位为0.79V，LiMgB_3C_3和LiBC之间的嵌锂氧化还原电位为0.74V。氧化还原电位对于锂离子电池的阳极活性材料是优选的。为了从动力学的角度进行讨论，用NEB方法估算了原子跃迁的势垒。结果表明，在（Li，Mg）BC中，Li和Mg原子的相互扩散是必要的，而相互扩散是（Li，Mg）BC动力学上的不利因素。

A Zintle phase of lithium magnesium borocarbaide, (Li,Mg)BC, was characterized for anode active materials of lithium-ion batteries by first-principles calculations. Systematic first-principles calculations in combination with the cluster expansion technique and Monte Carlo statistical thermodynamics simulations predicted redox potential for lithium insertion of 0.79V between MgB_2C_2 and LiMgB_3C_3, and of 0.74V between LiMgB_3C_3 and LiBC. The redox potential is preferable to the anode active materials of the lithium-ion batteries. Potential barriers of atomic jumps were estimated by the NEB method for the discussion from the kinetic point of view. It was found that mutual diffusion of Li and Mg atoms are necessary in (Li,Mg)BC and the mutual diffusion is a disadvantage of (Li,Mg)BC in kinetics.